Review and apply role recommendations for Cloud Storage buckets

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This page explains how to view, understand, and apply IAM role recommendations for Cloud Storage buckets. Role recommendations help you enforce the principle of least privilege by ensuring that principals have only the permissions that they actually need.

Before you begin

Required IAM roles

To get the permissions that you need to manage bucket-level role recommendations, ask your administrator to grant you the following IAM roles on the project:

  • Role Viewer (roles/iam.roleViewer)
  • Storage Admin (roles/storage.admin)

For more information about granting roles, see Manage access.

These predefined roles contain the permissions required to manage bucket-level role recommendations. To see the exact permissions that are required, expand the Required permissions section:

Required permissions

  • To view recommendations:
    • iam.roles.get
    • iam.roles.list
    • recommender.iamPolicyRecommendations.get
    • recommender.iamPolicyRecommendations.list
    • recommender.iamPolicyInsights.get
    • recommender.iamPolicyInsights.list
    • storage.buckets.getIamPolicy
  • To apply and dismiss recommendations:
    • recommender.iamPolicyRecommendations.update
    • storage.buckets.setIamPolicy

You might also be able to get these permissions with custom roles or other predefined roles.

Review and apply recommendations

You can review and apply bucket-level role recommendations with the Google Cloud CLI and the Recommender API.

Console

  1. In the Google Cloud console, go to the Cloud Storage Buckets page.

    Go to Buckets

  2. Find the Security insights column. If the column is not visible, click Column display options and select Security insights.

    The Security insights column shows a summary of all policy insights for a bucket. Each summary indicates the total number of excess permissions for all roles granted on that bucket.

    If there is a recommendation available to address any of the insights for the bucket, the Google Cloud console displays the Recommendation available icon.

  3. If there are recommendations to review, click a policy insight summary to open the Security recommendations pane. This pane lists all principals who have a role on the bucket, their roles, and any policy insights associated with those roles.

  4. Click a Recommendation available icon to get details about the recommendation.

    If the recommendation is to replace the role, the role recommendation always suggests a set of predefined roles that you can apply.

    In some cases, the role recommendation also suggests creating a new custom role at the project level. If a custom role recommendation is available, the Google Cloud console shows it by default. To switch to the predefined role recommendation, click View recommended predefined role.

  5. Review the recommendation carefully, and make sure you understand how it will change the principal's access to Google Cloud resources. Except in the case of recommendations for Google-managed service accounts, a recommendation will never increase a principal's level of access. See How role recommendations are generated for more information.

    To learn how to review recommendations in the console, see Review recommendations on this page.

  6. Optional: If the recommendation is to create a custom role, update the Title, Description, ID, and Role launch stage as needed.

    If you need to add permissions to the custom role, click Add permissions.

    If you need to remove permissions from the custom role, clear the checkbox for each permission that you want to remove.

  7. Take action on the recommendation.

    To apply the recommendation, click Apply or Create and apply. If you change your mind in the next 90 days, use the recommendations history to revert your choice.

    To dismiss the recommendation, click Dismiss, then confirm your choice. You can restore a dismissed recommendation as long as the recommendation is still valid.

  8. Repeat the previous steps until you have reviewed all of your recommendations.

gcloud CLI

Review your recommendations:

To list your bucket-level recommendations, run the gcloud recommender recommendations list command, filtering for only Cloud Storage bucket recommendations:

gcloud recommender recommendations list \
    --location=LOCATION \
    --recommender=google.iam.policy.Recommender \
    --project=PROJECT_ID \
    --format=FORMAT \
    --filter="recommenderSubtype:REMOVE_ROLE_STORAGE_BUCKET OR recommenderSubtype:REPLACE_ROLE_STORAGE_BUCKET"

Replace the following values:

  • LOCATION: The region where your Cloud Storage buckets are located—for example, us or us-central1.
  • PROJECT_ID: The ID of the Google Cloud project that contains your Cloud Storage buckets. Project IDs are alphanumeric strings, like my-project.
  • FORMAT: The format of the response. Use json or yaml.

The response is similar to the following example. In this example, all authenticated users (allAuthenticatedUsers) have the Storage Legacy Object Reader role (roles/storage.legacyObjectReader) on the bucket mybucket. However, this role hasn't been used in the past 90 days. As a result, the role recommendation suggests that you revoke the role:

[
  {
    "associatedInsights": [
      {
        "insight": "projects/123456789012/locations/us/insightTypes/google.iam.policy.Insight/insights/7849add9-73c0-419e-b169-42b3671173fb"
      }
    ],
    "associatedResourceNames": [
      "//storage.googleapis.com/my-bucket"
    ],
    "content": {
      "operationGroups": [
        {
          "operations": [
            {
              "action": "remove",
              "path": "/iamPolicy/bindings/*/members/*",
              "pathFilters": {
                "/iamPolicy/bindings/*/condition/expression": "",
                "/iamPolicy/bindings/*/members/*": "allAuthenticatedUsers",
                "/iamPolicy/bindings/*/role": "roles/storage.legacyObjectReader"
              },
              "resource": "//storage.googleapis.com/my-bucket",
              "resourceType": "storage.googleapis.com/Bucket"
            }
          ]
        }
      ]
    },
    "description": "This role has not been used during the observation window.",
    "etag": "\"7caf4103d7669e12\"",
    "lastRefreshTime": "2022-05-24T07:00:00Z",
    "name": "projects/123456789012/locations/us/recommenders/google.iam.policy.Recommender/recommendations/fbc885b7-f0a8-47e6-90fe-6141aa2c4257",
    "primaryImpact": {
      "category": "SECURITY",
      "securityProjection": {
        "details": {
          "revokedIamPermissionsCount": 1
        }
      }
    },
    "priority": "P1",
    "recommenderSubtype": "REMOVE_ROLE_STORAGE_BUCKET",
    "stateInfo": {
      "state": "ACTIVE"
    }
  }
]

Review each recommendation carefully, and consider how it will change the principal's access to Google Cloud resources. To learn how to review recommendations from the gcloud CLI, see Review recommendations on this page.

To apply a recommendation:

  1. Use the gcloud recommender recommendations mark-claimed command to change the recommendation's state to CLAIMED, which prevents the recommendation from changing while you apply it:

    gcloud recommender recommendations mark-claimed \
        RECOMMENDATION_ID \
        --location=LOCATION \
        --recommender=google.iam.policy.Recommender \
        --project=PROJECT_ID \
        --format=FORMAT \
        --etag=ETAG \
        --state-metadata=STATE_METADATA
    

    Replace the following values:

    • RECOMMENDATION_ID: The unique identifier for the recommendation. This value appears at the end of the name field in the recommendation. For example, if the name field is projects/example-project/locations/global/recommenders/google.iam.policy.Recommender/recommendations/fb927dc1-9695-4436-0000-f0f285007c0f, the recommendation ID is fb927dc1-9695-4436-0000-f0f285007c0f.
    • LOCATION: The region where your Cloud Storage bucket is located—for example, us or us-central1.
    • PROJECT_ID: The ID of the Google Cloud project that contains your Cloud Storage buckets. Project IDs are alphanumeric strings, like my-project.
    • FORMAT: The format of the response. Use json or yaml.
    • ETAG: The value of the etag field in the recommendation, such as "dd0686e7136a4cbb". Note that this value can include quotes.
    • STATE_METADATA: Optional. Comma-separated key-value pairs that contain your choice of metadata about the recommendation. For example, --state-metadata=reviewedBy=alice,priority=high. The metadata replaces the stateInfo.stateMetadata field in the recommendation.

    If the command succeeds, the response shows the recommendation in a CLAIMED state, as shown in the following example. For clarity, the example omits most fields:

    ...
    "priority": "P1",
    "recommenderSubtype": "REMOVE_ROLE_STORAGE_BUCKET",
    "stateInfo": {
      "state": "CLAIMED"
    }
    ...
    
  2. Get the allow policy for the bucket, then modify and set the allow policy so that it reflects the recommendation.

  3. Update the recommendation's state to SUCCEEDED, if you were able to apply the recommendation, or FAILED, if you could not apply the recommendation:

    gcloud recommender recommendations COMMAND \
        RECOMMENDATION_ID \
        --location=LOCATION \
        --recommender=google.iam.policy.Recommender \
        --project=PROJECT_ID \
        --format=FORMAT \
        --etag=ETAG \
        --state-metadata=STATE_METADATA
    

    Replace the following values:

    • COMMAND: Use mark-succeeded, if you were able to apply the recommendation, or mark-failed, if you could not apply the recommendation.
    • RECOMMENDATION_ID: The unique identifier for the recommendation. This value appears at the end of the name field in the recommendation. For example, if the name field is projects/example-project/locations/global/recommenders/google.iam.policy.Recommender/recommendations/fb927dc1-9695-4436-0000-f0f285007c0f, the recommendation ID is fb927dc1-9695-4436-0000-f0f285007c0f.
    • LOCATION: The region where your Cloud Storage bucket is located—for example, us or us-central1.
    • PROJECT_ID: The ID of the Google Cloud project that contains your Cloud Storage buckets. Project IDs are alphanumeric strings, like my-project.
    • FORMAT: The format of the response. Use json or yaml.
    • ETAG: The value of the etag field in the recommendation, such as "dd0686e7136a4cbb". Note that this value can include quotes.
    • STATE_METADATA: Optional. Comma-separated key-value pairs that contain your choice of metadata about the recommendation. For example, --state-metadata=reviewedBy=alice,priority=high. The metadata replaces the stateInfo.stateMetadata field in the recommendation.

    For example, if you marked the recommendation as having succeeded, the response shows the recommendation in a SUCCEEDED state. For clarity, this example omits most fields:

    ...
    "priority": "P1",
    "recommenderSubtype": "REMOVE_ROLE_STORAGE_BUCKET",
    "stateInfo": {
      "state": "SUCCEEDED"
    }
    ...
    

REST

These instructions assume that you have authenticated and set the GOOGLE_APPLICATION_CREDENTIALS environment variable.

Review your recommendations:

To list all available recommendations for your Cloud Storage buckets, use the Recommender API's recommendations.list method.

Before using any of the request data, make the following replacements:

  • PROJECT_ID: The ID of the Google Cloud project that contains your Cloud Storage buckets. Project IDs are alphanumeric strings, like my-project.
  • LOCATION: The region where your Cloud Storage buckets are located—for example, us or us-central1.
  • PAGE_SIZE: Optional. The maximum number of results to return from this request. If not specified, the server will determine the number of results to return. If the number of recommendations is greater than the page size, the response contains a pagination token that you can use to retrieve the next page of results.
  • PAGE_TOKEN: Optional. The pagination token returned in an earlier response from this method. If specified, the list of recommendations will start where the previous request ended.
  • PROJECT_ID: Your Google Cloud project ID. Project IDs are alphanumeric strings, like my-project.

HTTP method and URL:

GET https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/recommenders/google.iam.policy.Recommender/recommendations?filter=recommenderSubtype%20%3D%20REMOVE_ROLE_STORAGE_BUCKET%20OR%20recommenderSubtype%20%3D%20REPLACE_ROLE_STORAGE_BUCKET&pageSize=PAGE_SIZE&pageToken=PAGE_TOKEN

To send your request, expand one of these options:

The response is similar to the following example. In this example, all authenticated users (allAuthenticatedUsers) have the Storage Legacy Object Reader role (roles/storage.legacyObjectReader) on the bucket mybucket. However, this role hasn't been used in the past 90 days. As a result, the role recommendation suggests that you revoke the role:

{
  "recommendations": [
    "name": "projects/123456789012/locations/us/recommenders/google.iam.policy.Recommender/recommendations/fbc885b7-f0a8-47e6-90fe-6141aa2c4257",
    "description": "This role has not been used during the observation window.",
    "lastRefreshTime": "2022-05-24T07:00:00Z",
    "primaryImpact": {
      "category": "SECURITY",
      "securityProjection": {
        "details": {
          "revokedIamPermissionsCount": 1
        }
      }
    },
    "content": {
      "operationGroups": [
        {
          "operations": [
            {
              "action": "remove",
              "resourceType": "storage.googleapis.com/Bucket",
              "resource": "//storage.googleapis.com/my-bucket",
              "path": "/iamPolicy/bindings/*/members/*",
              "pathFilters": {
                "/iamPolicy/bindings/*/condition/expression": "",
                "/iamPolicy/bindings/*/members/*": "allAuthenticatedUsers",
                "/iamPolicy/bindings/*/role": "roles/storage.legacyObjectReader"
              }
            }
          ]
        }
      ]
    },
    "stateInfo": {
      "state": "ACTIVE"
    },
    "etag": "\"7caf4103d7669e12\"",
    "recommenderSubtype": "REMOVE_ROLE_STORAGE_BUCKET",
    "associatedInsights": [
      {
        "insight": "projects/123456789012/locations/us/insightTypes/google.iam.policy.Insight/insights/7849add9-73c0-419e-b169-42b3671173fb"
      }
    ],
    "priority": "P1"
  ]
}

Review each recommendation carefully, and consider how it will change the principal's access to Google Cloud resources. To learn how to review recommendations from the REST API, see Review recommendations on this page.

To apply a recommendation:

  1. Mark the recommendation as CLAIMED:

    To mark a recommendation as CLAIMED, which prevents the recommendation from changing while you apply it, use the Recommender API's recommendations.markClaimed method.

    Before using any of the request data, make the following replacements:

    • PROJECT_ID: The ID of the Google Cloud project that contains your Cloud Storage buckets. Project IDs are alphanumeric strings, like my-project.
    • LOCATION: The region where your Cloud Storage bucket is located—for example, us or us-central1.
    • RECOMMENDATION_ID: The unique identifier for the recommendation. This value appears at the end of the name field in the recommendation. For example, if the name field is projects/example-project/locations/global/recommenders/google.iam.policy.Recommender/recommendations/fb927dc1-9695-4436-0000-f0f285007c0f, the recommendation ID is fb927dc1-9695-4436-0000-f0f285007c0f.
    • ETAG: The value of the etag field in the recommendation, such as "dd0686e7136a4cbb". Use backslashes to escape quotes, for example, "\"df7308cca9719dcc\"".
    • STATE_METADATA: Optional. An object that contains key-value pairs with your choice of metadata about the recommendation. For example, {"reviewedBy": "alice", "priority": "high"}. The metadata replaces the stateInfo.stateMetadata field in the recommendation.

    HTTP method and URL:

    POST https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/recommenders/google.iam.policy.Recommender/recommendations/RECOMMENDATION_ID:markClaimed

    Request JSON body:

    {
      "etag": "ETAG",
      "stateMetadata": {
        "STATE_METADATA"
      }
    }
    

    To send your request, expand one of these options:

    The response shows the recommendation in a CLAIMED state, as shown in the following example. For clarity, this example omits most fields:

    ...
    "stateInfo": {
      "state": "CLAIMED"
    },
    "etag": "\"7caf4103d7669e12\"",
    "recommenderSubtype": "REMOVE_ROLE_STORAGE_BUCKET",
    ...
    

  2. Get the allow policy for the project, then modify the allow policy so that it reflects the recommendation.

  3. Update the recommendation's state to SUCCEEDED, if you were able to apply the recommendation, or FAILED, if you could not apply the recommendation:

    SUCCEEDED

    To mark a recommendation as SUCCEEDED, indicating that you were able to apply it, use the Recommender API's recommendations.markSucceeded method.

    Before using any of the request data, make the following replacements:

    • PROJECT_ID: The ID of the Google Cloud project that contains your Cloud Storage buckets. Project IDs are alphanumeric strings, like my-project.
    • LOCATION: The region where your Cloud Storage bucket is located—for example, us or us-central1.
    • RECOMMENDATION_ID: The unique identifier for the recommendation. This value appears at the end of the name field in the recommendation. For example, if the name field is projects/example-project/locations/global/recommenders/google.iam.policy.Recommender/recommendations/fb927dc1-9695-4436-0000-f0f285007c0f, the recommendation ID is fb927dc1-9695-4436-0000-f0f285007c0f.
    • ETAG: The value of the etag field in the recommendation, such as "dd0686e7136a4cbb". Use backslashes to escape quotes, for example, "\"df7308cca9719dcc\"".
    • STATE_METADATA: Optional. An object that contains key-value pairs with your choice of metadata about the recommendation. For example, {"reviewedBy": "alice", "priority": "high"}. The metadata replaces the stateInfo.stateMetadata field in the recommendation.

    HTTP method and URL:

    POST https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/recommenders/google.iam.policy.Recommender/recommendations/RECOMMENDATION_ID:markSucceeded

    Request JSON body:

    {
      "etag": "ETAG",
      "stateMetadata": {
        "STATE_METADATA"
      }
    }
    

    To send your request, expand one of these options:

    The response shows the recommendation in a SUCCEEDED state, as shown in the following example. For clarity, this example omits most fields:

    ...
    "stateInfo": {
      "state": "SUCCEEDED"
    },
    "etag": "\"7caf4103d7669e12\"",
    "recommenderSubtype": "REMOVE_ROLE_STORAGE_BUCKET",
    ...
    

    FAILED

    To mark a recommendation as FAILED, indicating that you were not able to apply it, use the Recommender API's recommendations.markFailed method.

    Before using any of the request data, make the following replacements:

    • PROJECT_ID: The ID of the Google Cloud project that contains your Cloud Storage buckets. Project IDs are alphanumeric strings, like my-project.
    • LOCATION: The region where your Cloud Storage bucket is located—for example, us or us-central1.
    • RECOMMENDATION_ID: The unique identifier for the recommendation. This value appears at the end of the name field in the recommendation. For example, if the name field is projects/example-project/locations/global/recommenders/google.iam.policy.Recommender/recommendations/fb927dc1-9695-4436-0000-f0f285007c0f, the recommendation ID is fb927dc1-9695-4436-0000-f0f285007c0f.
    • ETAG: The value of the etag field in the recommendation, such as "dd0686e7136a4cbb". Use backslashes to escape quotes, for example, "\"df7308cca9719dcc\"".
    • STATE_METADATA: Optional. An object that contains key-value pairs with your choice of metadata about the recommendation. For example, {"reviewedBy": "alice", "priority": "high"}. The metadata replaces the stateInfo.stateMetadata field in the recommendation.

    HTTP method and URL:

    POST https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/recommenders/google.iam.policy.Recommender/recommendations/RECOMMENDATION_ID:markFailed

    Request JSON body:

    {
      "etag": "ETAG",
      "stateMetadata": {
        "STATE_METADATA"
      }
    }
    

    To send your request, expand one of these options:

    The response shows the recommendation in a FAILED state, as shown in the following example. For clarity, this example omits most fields:

    ...
    "stateInfo": {
      "state": "FAILED"
    },
    "etag": "\"7caf4103d7669e12\"",
    "recommenderSubtype": "REMOVE_ROLE_STORAGE_BUCKET",
    ...
    

Understand recommendations

Each recommendation includes information to help you understand why the recommendation was made.

Console

To help you understand why the recommendation was made, the Google Cloud console shows the principal's permission usage, as reported by the policy insight associated with the recommendation.

To help you understand the impact of applying the recommendation, the Google Cloud console also shows a color- and symbol-coded list of permissions. This list indicates how the principal's permissions will change if you apply the recommendation. For example, it might show a list like the following:

The types of permissions associated with each color and symbol are as follows:

  • Gray with no symbol: Permissions that are in both the principal's current role and the recommended roles.

  • Red with a minus sign : Permissions that are in the principal's current role, but not in the recommended roles because the principal hasn't used them in the past 90 days.

  • Green with a plus sign : Permissions that are not in the principal's current role, but are in the recommended roles. This type of permission appears only in recommendations for Google-managed service accounts.

  • Blue with a Machine learning icon : Permissions that are in both the principal's current role and the recommended roles, not because the principal has used the permissions in the past 90 days, but because Recommender has determined through machine learning that they are likely to need those permissions in the future.

gcloud CLI

Each recommendation includes information to help you understand why the recommendation was made.

For details on the fields of a recommendation, see the Recommendation reference.

To see the permission usage that this recommendation is based on, view the policy insights that are associated with the recommendation. These insights are listed in the associatedInsights field. To view a policy insight that is associated with the recommendation, do the following:

  1. Copy the associated insight's ID. The ID is everything after insights/ in the insight field. For example, if the insight field reads projects/123456789012/locations/us/insightTypes/google.iam.policy.Insight/insights/7849add9-73c0-419e-b169-42b3671173fb, the insight ID is 7849add9-73c0-419e-b169-42b3671173fb.
  2. Follow the instructions to get a policy insight, using the insight ID you copied.

REST

Each recommendation includes information to help you understand why the recommendation was made.

For details on the fields of a recommendation, see the Recommendation reference.

To see the permission usage that this recommendation is based on, view the policy insights that are associated with the recommendation. These insights are listed in the associatedInsights field. To view a policy insight that is associated with the recommendation, do the following:

  1. Copy the associated insight's ID. The ID is everything after insights/ in the insight field. For example, if the insight field reads projects/123456789012/locations/us/insightTypes/google.iam.policy.Insight/insights/7849add9-73c0-419e-b169-42b3671173fb, the insight ID is 7849add9-73c0-419e-b169-42b3671173fb.
  2. Follow the instructions to get a policy insight, using the insight ID you copied.

View, revert, and restore changes

After you apply or dismiss a recommendation for a project-level role binding, that action appears in the recommendations history.

You can view the recommendations history for a bucket in the Google Cloud console:

  1. In the Google Cloud console, go to the Buckets page.

    Go to Buckets

  2. Find the Security insights column. If the column is not visible, click Column display options and select Security insights.

  3. Find the bucket whose recommendation history you want to view, then click the security insight summary in that row.

  4. In the Security recommendations pane that appears, click the Recommendations history tab.

    The Google Cloud console shows a list of previous actions on your role recommendations.

  5. To view details about a recommendation, click the expander arrow.

    The Google Cloud console shows details about the action that was taken, including the principal that took the action:

  6. Optional: If necessary, you can revert the recommendation, which undoes the changes in the recommendation, or restore a recommendation that you dismissed.

    To revert a previously applied change for a recommendation, click Revert. The Google Cloud console reverts the changes to the principal's roles. The recommendation no longer appears in the Google Cloud console.

    To restore a recommendation that was dismissed, click Restore. The recommendation becomes visible on the IAM page in the Google Cloud console. No roles or permissions are changed.

What's next